Plain porous bearings are utilized in many cases in motors and transmissions. Their production is cost-efficient and their application is easy. The limits of their area of application are specified by the maximum radial load. These radial loads depend on other bearing parameters such as e.g. the sinter materials, sliding speeds, lubricants, operating temperatures etc. In contrast to plain porous bearings, substantial slide bearings can usually be applied under higher radial loads and sliding speeds, since the lubricating film that builds up between the wave and the bearing can separate the friction partners under high loads as well. In the case of plain porous bearings, this works only conditionally, because under correspondingly high pressure, the lubricant will be compressed into the pores of the sinter material. This may lead to contact with foreign objects between the bearing and wave, increased friction, and ultimately to the breakdown of the bearing.
In the current state of the technology, a plain porous bearing per DE 199 37 567, among others, is known, which alternately distributes a highly compressed bearing bore with small porous contact surfaces, and axially-running, slightly compressed open-pore lubricant depots. By that invention, the lubricant depots are designed with at least two lengthwise grooves. The disadvantages of such plain porous bearings are that under specific operating conditions, a comparatively strong noise development occurs, because during operation the oil film can be stripped onto the groove, thereby no longer guaranteeing the supply of lubricant to the bearing gap.
This also applies to a plain porous bearing per DE 199 47 462 in which the grooves are bent in an acute angle towards the axle center of the bearing bore. DE 101 07 485 also depicts a plain porous bearing with the previously listed disadvantages.
In equivalent plain porous bearings corresponding to the state of the technology, the contact surfaces exhibit so-called hydrodynamic lubrication during operation, whereby, due to rising pressure, a separating lubricant film develops between the wave and the bearing. However, in the area of the open-pore zones the lubricant film is compressed into the open pores of the sinter material such that the wave in these areas is operated in what is called the mixed friction state. In this operating condition, among others, friction and wear are greater than during hydrodynamic operation.
The task of the invention is to reconcile the advantages of the substantial slide bearing (low friction, high sliding speeds) with those of the plain porous bearing by maintaining the advantages of the plain porous bearing (durability, lubrication through the lubricant deposited in the sinter material).